Physiological characterization of cotton genotypes (Gossypium herbaceum L.) for salinity at seedling stage

Cotton important cash crop and is moderately tolerant to salinity but its yield is markedly affected due to poor germination and subsequent abnormal plant development under severe saline conditions. Therefore, cotton accessions need to be screened and evaluated for salt tolerance. The genus Gossypium herbaceum has benefits of biotic and abiotic stress resistance along with higher yield. The present study aimed to investigate the physiological response of desi cotton (Gossypium herbaceum L.) cultivars viz., GN.Cot-25, G.Cot-21, V-797 and GShv-907/13 under four different salt concentrations viz., 0.8 dS/m, 3 dS/m, 7 dS/m, 10 dS/m at seedling stage (30 DAS). The physiological traits viz., membrane stability (%), leaf relative water content (RWC) (%), chlorophyll content (μmol m-2), photosynthesis rate (μmol CO2 m-2 sec-1), carotenoid content (mg g-1), transpiration rate (mmol m-2 sec-1) and stomatal conductance (μmol CO2 m-2 sec-1) were significantly reduced; while, surface wax content (μg/g of tissue) increased under different salt stress condition. However, GN.Cot-25 was able to maintain higher leaf relative water content (RWC), photosynthesis rate, chlorophyll content, carotenoid content, transpiration rate and stomatal conductance as compared to GShv-907/13 under of salt stress conditions whereas, the varieties, G.Cot-21 and V-797 showed moderate type of reduction for all parameters studied. Overall the study of physiological characterization proved to be effective in discriminating the desi cotton cultivars for salt tolerance.